Photocoagulation procedures for treating retinal tears, diabetic retinopathy and other retinal disorders are well known in the art. A well known slit lamp microscope configuration has been used to provide the visualization and base for such procedures.
Traditional ophthalmic surgical laser systems include a laser source that connects to a slit lamp-mounted delivery device via an optical fiber. The treatment often times is implemented using a visible aiming beam that individually marks the location at which the laser spot will impinge the target tissue. There are usually about 1500 laser pulses delivered in a standard pan retinal photocoagulation procedure, often totaling over 90 minutes of treatment across multiple sessions. Each of these laser pulses is activated by a depression of footswitch, and the parameters of the delivered laser pulse are controlled by a control panel. This single-shot “step and repeat” approach is time consuming, fatiguing, tedious, and uncomfortable for both the physician and patient.
Other attempts to improve the safety and speed of laser surgery have been proposed. These approaches require that the underlying laser system be inordinately complicated. For example, the simultaneous multiple spot delivery devices described in U.S. Pat. Nos. 5,921,981, 6,066,128 and 6,096,028 must employ a laser system capable of producing output powers considerably greater than those of a single spot system. This increase in laser power introduces additional and considerable expense, and raises possible safety concerns.
Similarly, in order to increase the speed of the manual procedure, the approach described in Intl. Pub. No. WO 2005/065116 A2 utilizes a single beam that is scanned using scanning optics to create a pattern of sequential therapeutic laser spots first represented by an aiming beam. The scanning of a single spot in the arrangement of a pattern allows the use of a lower power laser beam and source. In order to assure that the size and shape of the patterns of spots produced by both the aiming and therapeutic beams are identical, this device employs elaborate pattern sensing and associated feedback systems. While providing a means for improving laser surgery, it also increases the system cost and complexity. Moreover, there is no deliberate correlation between the physician's visual field of view through the microscope and the patterns of spots produced by the system.
Accordingly, there is a need for a safe, cost effective, adaptable and time-efficient approach to laser surgery that produces a pattern of treatment light that is reliably generated and that is closely linked to the physician's field of view.